Vortex flow control devices, or “vortex valves”, are used, for example in sewerage systems, for controlling fluid flow by a hydraulic effect without requiring moving parts. Such devices have a vortex chamber provided with an outlet at one axial end and an inlet arranged to cause a circulating flow in the vortex chamber which creates a vortex when a certain hydraulic condition has been attained.
At low flow rates, water entering through the inlet of a vortex flow control device passes through the vortex chamber to the outlet with substantially no pressure drop. At high flow rates, water enters through the inlet with enough energy to create a vortex in the vortex chamber which results in a significant pressure drop between the inlet and the outlet, thus restricting flow through the outlet. Therefore, the vortex flow control device automatically limits the rate of flow. Vortex flow control devices can be used, for example, to control the flow of stormwater in sewers such that equipment downstream of the device is not overloaded during periods of heavy rainfall.
Vortex flow control devices are commonly installed in a collection chamber (defined by a gully or manhole) in which rain water, drained from road surfaces and other paved areas, collects. An outlet pipe extends from a wall of the collection chamber to a sewer, and the vortex flow control device is mounted so that its outlet makes a water-tight connection with the end of the outlet pipe.
The hydraulic characteristics of a vortex flow control device can be controlled by varying the dimensions of the device. For example, the vortex chamber, inlet and outlet dimensions may be adjusted to tailor the flow rate at which a vortex initiates within the device. Accordingly, a vortex flow control device can be customized to suit the specific application in which it is to be used.
Similar customization may also be required for other devices installed in a collection chamber. For example, the dimensions of a filter module may be configured to define a residence time within the filter.
In general, such customization is both costly and time consuming, and is not easily altered once the device has been installed in the collection chamber.
The present invention seeks to provide an arrangement whereby customization of a vortex flow control device and other flow control modules is more readily achieved.